Application of an integrated phase Doppler interferometer/rainbow thermometer/point-diffraction interferometer for characterizing burning droplets
- Aerometrics, Inc., Sunnyvale, CA (United States)
A laser-based, nonintrusive diagnostic instrument has been developed for simultaneously measuring the velocity, size, temperature (refractive index) of burning droplets, and the gas-phase temperature field surrounding the burning droplet. The developed diagnostic is suitable for experimental studies involving single droplet/droplet array combustion. The size and velocity of the droplets are measured using the well-established phase Doppler interferometric technique. The temperature/refractive index of the droplets are determined by measuring the primary rainbow location with a linear charge coupled device (CCD) array. The gas-phase temperature distribution is inferred from interferograms obtained with point-diffraction interferometry (PDI). The three diagnostic techniques have been completely integrated to yield a single diagnostic instrument. New algorithms have been developed for extracting and normalizing the interferograms from noisy digital images. Methods for unambiguous phase unwrapping were also identified. The integrated diagnostic was tested by applying it to the case of isolated burning n-heptane droplets in motion. Using a combined experimental/theoretical approach, it was possible to extract the radial temperature profile of the gas phase surrounding the droplet in addition to the droplet velocity size, and temperature. The integrated diagnostic tool has significant potential for studying fundamental droplet combustion processes and for validating state-of-the-art droplet/spray combustion models.
- OSTI ID:
- 93188
- Report Number(s):
- CONF-940711--
- Country of Publication:
- United States
- Language:
- English
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